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I replaced my front brakes yesterday on my 83 240d. I used rebuilt calipers, new pads, rotors, brake lines and replaced wheel bearings on both sides. Initially, the job seemed a resounding success- the wheels spun like butter. Then, after bleeding the brakes both calipers are dragging, it's disappointing. This is the condition that lead me to change out my brakes in the first place.
Cracking the bleed screw does nothing to relieve the symptoms. Does this indicate a need for a new master cylinder? Does anyone know of another issue that can lead to this? I'm thinking both reman units are not likely to be bad. If I compress the pistons, the wheels spin freely until I step on the brakes again. Shoot.
 

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New pads will often drag until they bed down properly. Have you driven it yet? If not take a drive (cautiously) around the back roads of your area using your breaks and see if they bed down. If not the soft break lines would be the fist place I'd look. They can swell and only allow fluid to move in one direction.
 

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i agree with dude99 on the dragging brakes. however, i would rule the lines out because you say that when you open the bleed valve they are staying stuck.
based on what info you have given, i would say the rebuilt calipers are INOP.
 

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Some brakes are designed to drag a little at all times due to how close the pads ride on the rotors...how much drag are you talking about?
 

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I replaced my front brakes yesterday on my 83 240d. I used rebuilt calipers, new pads, rotors, brake lines and replaced wheel bearings on both sides. Initially, the job seemed a resounding success- the wheels spun like butter. Then, after bleeding the brakes both calipers are dragging, it's disappointing. This is the condition that lead me to change out my brakes in the first place.
Cracking the bleed screw does nothing to relieve the symptoms. Does this indicate a need for a new master cylinder? Does anyone know of another issue that can lead to this? I'm thinking both reman units are not likely to be bad. If I compress the pistons, the wheels spin freely until I step on the brakes again. Shoot.
Yes the Master is stuck.
 

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On cars of this vintage a little drag is normal. The only thing that moves the pad away from the rotor is the compliance of the rubber piston seal. On newer cars they found ways to pull it back a little further to reduce drag and improve fuel consumption.

Can you manually move the pistons easily? Remove the two bolts that hold the caliper. Grasp the caliper and move with a twisting motion. Do the pistons move back? If yes, I'd say all is normal.

You'll want to follow the advice of bedding-in the pads. I don't know how Mercedes recommends to do this.

After this is done, try driving the car in a manor where you use little or no braking for perhaps 10 miles. Feel the rotor temperature. If it is not hot, all is normal.
 
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